From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=3.0 tests=DATE_IN_PAST_06_12, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CC500C43612 for ; Tue, 18 Dec 2018 11:40:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A4B81217D9 for ; Tue, 18 Dec 2018 11:40:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726724AbeLRLkx (ORCPT ); Tue, 18 Dec 2018 06:40:53 -0500 Received: from mga03.intel.com ([134.134.136.65]:62099 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726583AbeLRLki (ORCPT ); Tue, 18 Dec 2018 06:40:38 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 18 Dec 2018 03:40:38 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,367,1539673200"; d="scan'208";a="304764717" Received: from aubrey-skl.sh.intel.com ([10.239.53.9]) by fmsmga005.fm.intel.com with ESMTP; 18 Dec 2018 03:40:36 -0800 From: Aubrey Li To: tglx@linutronix.de, mingo@redhat.com, peterz@infradead.org, hpa@zytor.com Cc: ak@linux.intel.com, tim.c.chen@linux.intel.com, dave.hansen@intel.com, arjan@linux.intel.com, aubrey.li@intel.com, linux-kernel@vger.kernel.org, Aubrey Li Subject: [PATCH v6 2/3] proc: add AVX-512 usage elapsed time to /proc/pid/status Date: Tue, 18 Dec 2018 12:22:17 +0800 Message-Id: <20181218042218.8653-2-aubrey.li@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181218042218.8653-1-aubrey.li@intel.com> References: <20181218042218.8653-1-aubrey.li@intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org AVX-512 components use could cause core turbo frequency drop. So it's useful to expose AVX-512 usage elapsed time as a heuristic hint for the user space job scheduler to cluster the AVX-512 using tasks together. Example: $ cat /proc/pid/status | grep AVX512_elapsed_ms AVX512_elapsed_ms: 1020 The number '1020' denotes 1020 millisecond elapsed since last time context switch the off-CPU task using AVX-512 components, thus the task could cause core frequency drop. Or: $ cat /proc/pid/status | grep AVX512_elapsed_ms AVX512_elapsed_ms: -1 The number '-1' indicates the task didn't use AVX-512 components before thus unlikely has frequency drop issue. User space tools may want to further check by: $ perf stat --pid -e core_power.lvl2_turbo_license -- sleep 1 Performance counter stats for process id '3558': 3,251,565,961 core_power.lvl2_turbo_license 1.004031387 seconds time elapsed Non-zero counter value confirms that the task causes frequency drop. Signed-off-by: Aubrey Li Cc: Peter Zijlstra Cc: Andi Kleen Cc: Tim Chen Cc: Dave Hansen Cc: Arjan van de Ven --- arch/x86/kernel/fpu/xstate.c | 34 ++++++++++++++++++++++++++++++++++ fs/proc/array.c | 5 +++++ 2 files changed, 39 insertions(+) diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 87a57b7642d3..d084b1dc80a6 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -7,6 +7,7 @@ #include #include #include +#include #include #include @@ -1245,3 +1246,36 @@ int copy_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf) return 0; } + +/* + * Report the amount of time elapsed in millisecond since last AVX512 + * use in the task. + */ +void avx512_state(struct seq_file *m, struct task_struct *task) +{ + u64 timestamp = task->thread.fpu.avx512_timestamp; + s64 delta; + + if (!timestamp) + delta = -1; + else { + WARN_ON_ONCE(jiffies_64 < timestamp); + delta = div_u64(jiffies64_to_nsecs(jiffies_64 - timestamp), + NSEC_PER_MSEC); + } + + seq_put_decimal_ll(m, "AVX512_elapsed_ms:\t", delta); + seq_putc(m, '\n'); +} + +/* + * Report CPU specific thread state + */ +void arch_task_state(struct seq_file *m, struct task_struct *task) +{ + /* + * Report AVX512 state if the processor and build option supported. + */ + if (cpu_feature_enabled(X86_FEATURE_AVX512F)) + avx512_state(m, task); +} diff --git a/fs/proc/array.c b/fs/proc/array.c index 0ceb3b6b37e7..dd88c2219f08 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -392,6 +392,10 @@ static inline void task_core_dumping(struct seq_file *m, struct mm_struct *mm) seq_putc(m, '\n'); } +void __weak arch_task_state(struct seq_file *m, struct task_struct *task) +{ +} + int proc_pid_status(struct seq_file *m, struct pid_namespace *ns, struct pid *pid, struct task_struct *task) { @@ -414,6 +418,7 @@ int proc_pid_status(struct seq_file *m, struct pid_namespace *ns, task_cpus_allowed(m, task); cpuset_task_status_allowed(m, task); task_context_switch_counts(m, task); + arch_task_state(m, task); return 0; } -- 2.17.1